Booster device for operating well tools



April 18, 1961 T. w. ROYER 2,979,904

BOOSTER DEVICE FOR OPERATING WELL TooLs Filed April 27, 1959 2 sheets-sheet 1 3,2/ QI :a 64

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I I THURBER w. ROYER d @M @fr ATTORNEY April 1s, 1961 T. w. ROYER 2,979,904

BOOSTER DEVICE FOR OPERATING WELL TOOLS v Filed April 27, 1959 2 Sheets-Sheet 2 IN V EN TOR.

THURB E R W. ROYER ATTORNEY 2,979,904 BOOSTER DEVICE FOR OPERATING WELL 'IAOOQS Thurber W. Royer, Arcadia, Calif.,V assgnor'tonAeroietgrileral Corporation, Azusa, Calif., a corporation of Filed Apr. 27, 1959, Ser. No. 809,256:

16 Claims. (Cl. 60-54.5)

The present invention relates to an operating device for tools adapted to be used under hydrostatic pressure. The device of the invention will be hereinafter described with reference to the operation of an oil well tool by way of illust-ration but not by way of limitation of its field of use.

While there are a variety of well tools, the invention will be described with reference to the setting in position of roil well bridging plugs which are widely used in the art and are particularly adapted to operation by the de-y vice.

A bridging plug is a tool of elongated cylindricalshape provided with a thick sleeve of rubber offresilient material around its outer surface and intermediate the length thereof. The sleeve is ttedbe'tween upper and lower anges on the tool which may beforced together to thereby axially compress` and radiallyexpand thel sleeve into engagement with the well casing. Bridging" plugs are also commonly tted with either a single or double row ofslips, Vwhich are serrated `wedgelike elements mounted on a conical seat aro-und the tool and forced into positive gripping engagement with the well casing. The bridging plug is therefore eiectivet-o seal .the ,bore of the well and also to prevent movement of the yplug up r down in the well due to existence of a pressure differential between the surfaces of the plug. v

The force required to expand the sleeve of thebr'idging plug into engagement with the well casing! is lessv than that required to engage the slip Yserrations in thel well casing. It is therefore the generalobject offthis invention to provide an operating device utilizing the hydrostatic pressure existing in the well at the` point at which" the bridging plug or other similar tool/'is to beV set to furnish hydraulic pressures reqnired` to operate the tool. Y Y

It is another object of the invention to provide an operating device in which hydraulic pressurev to operate a well tool is developed ina sequence, vone pressure being sufficient to set elements 0f the tool requiring a/lowery pressure, followed by a higher pressure required to 'set other elements of the tool preferably `followed byva still higher pressure effective to release the operating? tool from the well tool.

It is a further object ofthe invention to provide an operating device for tools functioning under a hydro-static pressure which is rapid land eiective in action andi's adapted to operate any tool of the kindoperated under hydrostatic pressures by uid pressure introduced into the tool. l

With the above and further objects andfeatures of invention in View which will appear from the following' specification, the invention comprises an operating device for tools adapted to functionI under a hydrostatic pressure, said device having a leasing providing a cylin-v drical cham-ber open at one end and containinga fr ee piston upon which the hydrostaticl pressurefacts, a `par. tition in the chambervproviding a res'ervoirbetween it and the free piston for -a body of uid pressurized by the vsaid maximum diameterv section.

2,979,904 Patented Apr. 18,1961

2 hydrostatic pressure. A compound diameter cylinder is connected by a demand-valve controlled passage to said reservoir, said cylinder having a section of maximum diameter `less than that of the free piston land having successive'sections of progressively smaller diameter than a A piston actedv on by the` pressurized fluid is tiitted with a piston rod extending into, said compound `diameter cylinder and carries a comf positel piston, the elements of which are initially secured together Vby 'automaticallyV releasable means and which progressively work in corresponding sections of the com-y pound diameter cylinder. Means` are provided to Vlead hydraulic uid from the length of smallest diameter of said compound diameter cylinder to the tool to be operated. In the drawings: Fig'. 1 is a central vertical section view'through the operating device of the invention, the lower portion being broken through to reduce the length of the iigure. Fig. 1a is a section view showing the lower end of Fig. l.

Fig. 2 is a fragmentary sectional view of the portion of the device indicated by the dotted line 2 in Fig. 1, drawn on a larger scale.

Fig., 3 isa section view drawn on a larger scaleof the portion of the device indicated by the dotted line 3 in Fig. 1.

Fig. 4 is afragmentary section view showing the manner of attaching the device to a suspending cable.

Fig. 5 isa vertical half section view of an oil tool adapted to bey operated by the device of the invention, shown partly set, the slips being still retained on their. seats by shear pins. Y

Fig. 46 is a plan view of a mechanical arrangement for operating a vvalve initiating operation of the device and actuated by a go-devihand Fig."7 is a central vertical section view through the parts shown in Fig. 6. l

Referring now to Fig. 1, the numeral 10 indicates the elongated casing of the novel operating device of the invention. The casing is preferably tted with an apertured disc 11 `at its upper end and with a xed partition or bulkhead 12 in its upper portion 10a. The lower portion 10b of the casing comprises an upper lengthv 13 which may be Welded at its upper end, as indicated at 14, to the` bulkhead 12 and at its lower` end is screwed to an lin terior cup-shaped member 15 having va transverse head provided withapertures for air passage .around a central opening for the support of interior pa-rts later described-.-

A lower length 17 of the lower portion 10b of the casing 10 is connected atits upper end to the interior cuprshaped member 15 as shown at 17a by a threaded joint. l g y The lower end of casinglength 17 is closed by a plug 18 -shown in Fig. la to which the casing end may be` welded as indicated at 19.- Plug 18 is provided with an axial bore- 19a and a downwardly extending tubular extension-20 lwhich maybe formed integral therewith, or as indicated at 21, welded thereto.

A tubular suspending fitting 22 is screwed into the bore quire to be charged with hydraulic uid and the arrange- Y ments made 4forthis purpose will latter appear. v

A supporting tube generally indicated at 27 is screwe at its "lower'end' into a threaded socket in the fixed bulk- A head 12 as indicated at 28 in Fig. 1, the bore 29 of the the bore of the fitting 22 may be4k lower end of the support tube 27 being aligned with a central opening 30 in the fixed bulkhead.

As shown in Fig. 2 an exchangeable liow control nozzle 31 is screwed into a recess in the lower end of the support tube 27. An O ring seal 32 is compressed between the end of the support tube 27 and the bottom of the threaded socket in the bulkhead 12 in which it is mounted.

As shown in Fig. 4 the upper end of the support tube 27 is threaded at its upper end 33 and engaged n a threaded ring 34 connected by yoke arms 35 to a frustoconical socket 36 in which the end of an electric cable 37 is secured as for instance by frayng out the end of the cable in the conical socket and setting the ends in solder poured into the socket. A conductive wire 38 wound in the cable is connected to electrical igniting means for a slow burning propellant charge positioned in the support tube 27 which will be now specifically described.

Referring now to Fig. 2 it will be noted that the support tube 27 is built up of a plurality of sections screwed together and pinned by set screws 27a so that it may be readily unscrewed from the bulkhead 12 to change 'the flow control nozzle 31 and may also be broken down into components to give access to parts contained therein.`

The top section 39 is shown in Fig. 4 as being provided with a threaded socket opening into its upper surface in which is mounted the gland nut 40 having an axial passage for the lead 41 connected to conductive wire 38, and ground wire 42 which pass through an insulated bushing 43, a rubber packing 44 compressed by theV gland nut 40 into sealing engagement with the wires which extend through a restricted passage 45 in the head of top section 39 into the enlarged diameter bore 46. The ground wire 42 is secured at its upper end in a short hole 47 drilled into the upper end of the top section 39.

The wires 4 1 and 42 are embedded in a thin rod-like grain 48 of slow burning propellant, the ends of the wires being connected by a short length (not shown) of high resistance wire by heating of which the grain may be ignited, when electric current is sent therethrough by closing a switch positioned at the surface of the well.

It is seen in Fig. 2 that the lower end of top section 39 of the support rod 27 is screwed to a section 49 which is formed to provide a cylinder 50, a passage 51 connected at its upper end by port 51a to the lower end of the bore 46 and its lower endby port 51b to the lower end of the cylinder 50. A wire mesh screen 46a is placed at the lower end of bore 46 to prevent debris entering the port connecting passage S1 to the lower end of Vbore 46.

A piston 52 is mounted in cylinder 50 and a piston rod 53 threaded thereinto passes through a hole drilled through the upper end of the lowest section 54 of the support rod 27.

The section 54 contains valve means to open a passage from the space above the bulkhead 12 into the space below it. The valve means comprise a piston-like member 55 sliding in fluid tight relation in the bore 56 of section 54 of the support tube 27 and mounted on the piston rod 53. Ports 57 in the wall of section 54 immediately above the bulkhead 12 admit liuid to the bore 29 of section 54 from which the uid flows through the lower portion of bore 29 and central opening 30 in the bulkhead 12. In closed position valve 55 closes ports 57 as indicated in dotted lines in Fig. 2.

` A free piston 58 is shown in Fig. 1 as positioned in the space above the bulkhead 12 in iiuid tight sliding arrangement with the inner surface of the casing 10 and the outer surface of the support tube 27. Hydraulic fluid loaded into the space between the bulkhead 12 and piston 58 before the setting tool is lowered into the well will therefore be under the static pressure of the liquid in the well which may reach high values, but the fluid will be trapped in the space until valve S is operated to open the passage through ports 57 and the central aperture 30 through the bulkhead. Fluid is introduced into the space under piston 58 by the filling port 59 and passage 60 provided in the bulkhead 12. Port 59 1s sealed after filling the space by a threaded plug 61. The space in the casing 13 below bulkhead 12 constitutes a working cylinder 62.

A working piston 62a is arranged in the Working cylinder 62 in sliding but fluid tight relation to the inner wall of the casing 13. The piston 62a is provided with a narrow central opening 63a leading into a vertical chamber 63, the lower portion of which provides a threaded socket.

A piston rod 64 threaded at its upper end is screwed into the threaded socket of vertical chamber 63. The piston rod 64 is preferably though not necessarily tubular, the interior passage being indicated at 65 for reasons later discussed. A ball check valve 66 is positionedin chamber 63 and resiliently held by coil spring 67 against the edge of opening 63a, the lower end of the spring being supported on the upper end of the tubular piston rod 64.

A two diameter cylinder 68 is mounted in the lower portion 17 of casing 10 and comprises a `thick walled length of small diameter 69, the lower end of which is exteriorly threaded and screwed into the threaded bore in plug 18 and the upper end of which extends into and secured to a cylinder of greater diameter 70. The upper end of cylinder.70 extends through the central opening in head 16 of member 15 and is securely positioned thereby. The exterior upper end of cylinder 70 is threaded and closed by a cap71 screwed on the threaded end of cylinder 70.

Cap 71 is centrally vertically bored. Piston rod 64 extends throughtthe bore in cap 71 and an O ring seal 72 is mounted in cap 71 in a groove 73 around the bore therethrough and provides a fluid tight seal between the cylinder cap 71 and piston rod 64.

A composite piston 75 is arranged at the lower end of the piston rod. The end 76 of the piston rod 64 is solid and acts as a high pressure piston when working in the smaller diameter cylinder 69. An annular piston element 77 mounted around the end 76 of the piston rod 64 provides with the end 64 of the piston rod 76 an intex mediate pressure piston working in the cylinder 70 of greater diameter than cylinder 69. 0 ring seal 78 mounted in a groove 79 in annular element 77 seals against leakage between ring 77 and the surface of piston rod end 76 and 0 ring seal 80 in a peripheral groove in ring 77 sealing against leakage between the ring 77 and the wall of the greater diameter cylinder 70. The annular element 77 is mounted on the end 76 of the piston rod 64 by a shear pin 81.

The bore 65 of the piston rod 64 is connected to the space between the two diameter piston 75 and cap 71 by lateral ports 74.

An oil well tool of a type suitable for operation by the operating device of the invention is indicated in Fig. 5. The tool comprises a hollow mandrel member A having an upper shoulder B and a depending skirt member C of greater diameter than mandrel A. A force member member has an inturned head flange D, the space E defining a pressure chamber connected to the interior of the mandrel by ports F in the wall of the mandrel. Upper and lower separate wedge shaped slips S abut shoulder B and flange D, and are connected to conical seats G by shear screws S1. The wide ends of the conical seats G abut the upper and lower ends of a sleeve S1 of resilient material surrounding and sldable on the surface of the mandrel.

The mandrel is provided'at its upper end with a neck H which ts closely over the tubular suspending fitting 22 of Fig. la, of the setting device and is releasably secured thereto by a U-shaped shear pin J received in a peripheral groove in the outer surface of the neck H, and in aligned holes in the tubular extension 20 of plug 18.y The'tool is 'maintained in uid tight v,engagement with the' surface'of the suspendingiitting 22 by the engage ment of the O rings with' the ne'ck H.

The interior cavity of the mandrel is filled with hydi'aulic uid which maybe retained 'therein by frangible disc K held against its seat by a' threaded ring. Y v

It will be appreciated that on' the forcing of hydraulic uid from the operating 'device of the invention into the tool the disc K will be ruptured. Pressure uid forced' into the interior of the mandrel and thence into 'chamber E will force ange D upwardly exertingH equal and opposite downward force on shoulder BV on the mandrel. Force is' transmitted through the slips S and shear screws S1 and conical seats G to the 'resilient sleeve SL shortening' it and radiallyexpanding it int engagement with the well casi ing WC after which the shear pins'S'l yield and the 'slips are driven further onto the conical'seat's until firmly engaged lwith the well casing, Furth'eriricrea'se in'p'rsL sure'will thereafter act between the tool', whichy cannot move, and the setting device which is 'free' 'to move 'upA wardly, until the pressure is suliicient to-shear pin I.

It is to be noted that the well tool shown' in Fig. 5` forms no part ofthis invention and is described to make clear the type of tool capable of operation by the device of this invention. The tool shown does not represent any specific construction and illustrates only those parts operi ated by the pressure fluid supplied by the device of the invention which is to be considered widelyl as a source of power for various types of toolsoperated under hydrostatic pressure, for instance, on a deep sea bottom. The means for operating the valve admiiting hydraulic iluid into theoperating device under the static 'pressure of the liquid in the well or deep'sea bottom has been described with reference to the use of gas pressure, developed by a charge of slow burning propellant ignited by'electrical mean's'operated 'from the surface, but it is obvious that ignition of Vthe charge may be eifected by a cartridge red byv ago-devil by utilizing arrangements of parts within the skill of 'the art to provide, and any such means are held to -fall within the 'scope of this invention.

In-place of operating the valve admitting hydraulic fluid into the operating device under the static pressure ofthe well liquid by gaseous pressure, it may be preferred to operate the valve bythe use of mechanical means operated by a go-devil. Such an arrangement is shown inFigs 6 and 7 in which the modied support tube' 82 is a unitary'length of tube from its fitting with` thebulkhead I2(not shown in Fig. 7) to the upper end shown in Fig. 7. Ports are arranged communicating through the 'wall ofthe tube'82 with its bore in an area adjacent the' upper surface of the bulkhead 12 as was shown in Figs. l and 2.'

The' ports are closed until the device is operated by the lower end of a rod 83 which extends through the support tube 82 Yand projects from the upper end thereof. Rod 831isfurnished with a head 84.

A bridge fittingy 85 is mounted on the apertured disc 11a. A lever 86 is mounted at one end on a pivot 87 passing through the eye of a bolt 88 extending upwardly from lthe horizontal member 85a, the bridge fitting 85k and is formed with a ring portion 89 through which the cable 37a extends.

The-free end of lever'86 rests on a thrust pin 90 resting" on the tail of a lifting lever 91 pivoted on a stud 92 secured to and projecting downwardly from the horizontal member 85a. The opposite end of the lever is formed with' a forked head 93 engaging under opposite sides of head 84. A go-devil 94 hitting lever 86 will cause the rod 83 to be 'raised and the lower end of the rod to be drawn clear of theports at the lower end of the support tube-82.

In' order to provide space for parts acting to'raise the rodi83` thevupper end of the support tube 82:'is engaged wi'tlran'internally threaded coupling member 82a which extends: throughfanlaop'ening inthe horizontakjmember 98 'placed 'in a central 'threaded recess in the upper end of the support tube` 82 and compressed between the wallv of the recess and' the surface of the rod 83 by a threaded pressure ring' 99 which is screwed down upon the packing;

OperationlnV the Ypreparation for use of the operating ,deviceof the 'invention after a" pr'eviou'siuse, the well'tool or other: toolto be operated under hydrostatic pressure is lled' withhydrali'cuid. j l l The chamber' 'between the bulkhead 12 and free pistonj 58 is also filled with hydraulic fluid as is the space'in the two diameter cylinder. The operation of filling the space under the free piston 58 inthe setting tool with hydraulic tluid will result in moving the free piston 58'` against the underside-of the apertured disc 11. SectionY 13 of the casing is unscrewed fromy the lower section 17,1 the cap 71 unscrewed from the upper end of cylinder 70 and the composite piston 75 withdrawn from the eylin' der. This operation will empty the oil trapped between the top of the annular piston element 77, the piston rod 64 and the cap 71 and enable the shear pin 81 if frac-` tured by the previous useof the device to be replaced inthe reassembled composite piston 75, which may then be" replaced in the cylinder and the cap 71 replaced; Thef casing sections 13 and 17 may then be screwed together'w and the. two diameter cylinder 68 filled with hydraulic'- uid through the threaded lower end 26, moving the come" posite piston to the inward end of its travel. Thehydraulic fluid maybe retained in the two diameter cylindeu 68 by corking the lower end of the bore of the suspending tting 22 or by providing a plug valve 18a in the plugI 18` closing the bore therethrough.

A fresh grain of slow burning propellant v48 is placed in position by unscrewing the support tube 27, slacking back theset screw 27a previously holding the top section 39 against being unscrewed, vremoving the gland nut 40` vand wires 41 and 42. y lThe fresh grain may then be put in place with its'V wires threaded through the gland nut which is then put -baok in place and the upper section assembled into' the support tube 27 which is then screwed back into" bulkhead 12 and the wires properly connected. j While the use of a composite piston having concentric elements secured together by a shear pin is speciiically'r g described it is to be understood that any other means such as vspring pressed detents may be used to hold the' concentric elements for movement with the small diaventing plug in the cap71 would obviate thev necessityv for unscrewing the cap to empty trapped oil and replace the shear pin 81. To use the operating device after a previous use or when initially used, it is prepared asi previously described by being lllled with hydraulic iluid and-tted with a grain of slow burning propellant withmeans for igniting it and with a shear pin in place in the composite piston 75. The pressure chambers in the tool to be operated are also filled with hydraulicy fluid and the tool attached by the shear pin to the device." A llow nozzle 30 suited lto the needs of the job, a largeY orifice being employed for light down hole pressures and a smaller' oriiicetor high down hole pressuresA is inserted in assembling 'the tool, and' a shear pin yield-p,

ing at' the 'pressure'estimated to 4besuticient'to complete f? the lower pressure phase of the job is placed in position in the composite piston 75.

Obviously if it is desired to operate a tool'which can be hoisted after operation still attached to the device, any suitable means to relieve excessive pressure may be provided. If a heavy tool such as a deep sea grab for securing samples of the sea bottom is to be operated, the tool could be secured to a heavy cable and be detached from the operating device which would vbe suspended by a separate cable.

The operating device and attached tool are then lowered to the point of operation and the grain of slow burning propellant ignited by the use of electric current or of a go-devil to open the valve 55 resulting in the hydraulic fluid under the hydrostatic pressure, which at a depth of about 2000 feet for instance, amounts to over 1000 lbs. per sq. in., acting in the working cylinder 62 and forcing the working. cylinder downward. Assuming the working piston 62a is three times the diameter of the composite piston and that the latter is three times the diameter of the end 76 of the piston rod, a pressure of over 9000 lbs. per sq. in. is available to operate the tool. In the case of the bridging plug illustrated the resilient sleeve SL would be squeezed tight against the well casing by the lower pressures, the shear pin 81 would then shear as resistance to movement of the telescopic parts of the tool increased. The higher pressure developed yby the piston 76 in the smaller diameter cylinder 69 will be effective to fracture the shear pins S1 and set the slips. y

Although the action described would take place if a solid piston rod 64 were to be used, it is evident thatl the space between the cap 71 and rear of the composite piston 75 would be Void of fluid so that when the shear pin 81 in the composite piston gives way, which it might do before piston rod and 76 entered small diameter cylinder 69, the outer portion or annular element 77 .thereof would then be forced toward cap 71 by hydraulic fluid under the pressure of the downwardly moving piston rod and hydraulic iiuid back ow from parts which had been operated by the fluid under pressure of the composite piston 75. The least disadvantage of the temporary cessation of delivery'of effective pressure to the tool would be a break in the time of operation of the tool. The advantage of the provision of delivery of oil to 'the space behind the composite piston is that when the annular element 77 shears from the piston end 76, the hydraulic -tluid trapped behind it by check valve 66 holds the annular element and ensures continued delivery of hydraulic tiuid but at a higher pressure to the tool.

Preferred embodiments of the invention have been described 4and illustrated by way of example but not as limitative of the invention since various modifications will be evident to those skilled in the art and may be made without departing from the scope of the invention as defined by the appended claims.

I claim:

1. An operating device for tools `functioning under hydrostatic pressure, comprising: a cylinder open at one end to the hydrostatic pressure; a free piston working in said cylinder; a wall closing the opposite end of said cylinder, the space between said wall and free piston constituting a reservoir for fluid pressurized by said hydrostatic pressure; said wall having a passage leading fluid out of said reservoir; valve means effective to initially close said passage; means for moving said valve to open said passage; a compound diameter cylinder having a plurality of sections each of progressively less diameter than the preceding section, the compound cylinder having a maximum diameter less than that of the free piston; a piston displaced by fluid from said reservoir and having a piston rod permanently secured thereto and extending into said compound diameter cylinder; a composite piston mounted on said piston rod and work- -8 ing in said compound diameter cylinder, said composite piston having coaxiallyy nested elements the outermost of which works in thesection of greatest diameter, and the innermost of which works in the section of least diameter of said compound diameterv cylinder; automatically Vreleasable means initially `holding said cornposite piston elements in alignment; and conduitmeans adapted to connect the tool to be operated to the cylinder of least diameter of said compound diameter cylinder.

2. An operating device as set forth in claim 1 and in addition comprising: a flow control nozzle removably mounted in the passage leading uid out of said reservoir.

3. An operating device as set forth in claim l and in which said piston rod is provided with an axial bore communicating at its upper end with the uid issuing from the reservoir and at its lower end communicating with the space between said composite piston mounted on said piston rod and the head of said composite diameter cylinder; and a check valve at the upper end of said axial bore to prevent reverse tiow of uid therethrough.

4. An operating device for tools functioning under hydrostatic pressure as set forth in claim l and in addition comprising: a flow control nozzle removably mounted in the passage leading hydraulic fluid from said reservoir.

5. An operating device as set forth in claim 1 and in which said automatically releasable means holding the composite piston elements in alignment comprises af shear pin fitted in a hole drilled diametrically through all elements of said composite piston.

6. An operating device for tools functioning under hydrostatic pressure, comprising: a cylindrical casing open to the entry of liquid at hydrostatic pressure at its upper end; a free piston sliding in liquid tight engagement with the wall of said casing; a transverse wall closing said casing but below said free piston, the space between said piston and wall constituting a reservoir for hydraulic fluid pressurized by said ambient hydrostatic pressure; a working cylinder positioned in said casing below said wall; said wall having a passage connecting said reservoir to said working cylinder; valve means controlling said passage; means for opening said valve to enable the pressurized hydraulic fluid to flow into said working cylinder; a compound cylinder mounted coaxially with the working cylinder in said casing and having a plurality of lengths of progressively less diameter, and a maximum diameter less than that of the working cylinder; a cylinder cap separating said rst cylinder of the compound diameter cylinder from the working cylinder and provided with a central opening therein; a piston working in said working cylinder; a piston rod secured to said working piston and extending through the opening in said cap in fluid tight relation therewith into said compound cylinder; a composite piston mounted on the piston rod within said compound cylinder, said composite piston having coaxially nested piston elements, the outer of said piston elements having a diameter fitting the length of greatest diameter of said compound cylinder; automatically releasable means initially holding said composite piston elements in alignment; means connecting the device to a suspending member; and means for connecting the tool to be operated in uid tight relation to the device to receive the hydraulic fluid at maximum pressure from the cylinder' of least diameter of the compound cylinder of the device.

7. An operating device for tools functioning under hydrostatic pressure, comprising: an elongated cylindrical casing having a fixed partition provided with an axial opening therethrough extending across an upper portion of said casing; a support tube axially positioned in the upper portion of the casing with its lower end secured in said partition with the bore thereof in alignment with the axial opening therein; a free piston spaced from said fixed partition and slidably mounted on said support tube in fluid tight relation tothe wall of the cylindrical casing and ythesurface of vsaid support tube, hydraulicuid being positioned inthe kupper portion` of the.. casing .bei tweenV said free piston and partition, the upper surface of said free piston being under -the hydrostatic-pressure of the liquid in the well; passages throughthe wall of the support tube adjacent the. uppersurface of s-aid. partitionv and leading into the bore of .the.support.tube;. ow controlling means arrangedwithin said support tube adapted to..close` said passages; meansoperated fromv the ground surface for moving said vo'wcontrol .means to enable hydraulic iluidto flow out of .said space between the vfree pistonv and partition.. under thepressure of .the

hydrostatic pressure in the .well;f aworking `piston in said cylindrical. casing below said partition in fluid tight sliding relation .to thewall of thecasing;.the .space above said working pistonconstituting a-working cylinder receiving. the hydraulicuid flowing .outfofwthe spacev between the freepiston vand xedpartition; a piston rod Vsecured at its upper end to said working piston;a vcompound diameter cylinder arranged coaxially with the working cylinder and having a plurality Iof lengths of progressivelydess diameter, and a maximum diameter less than that of the working cylinder; a cylinder'. cap separating the rst cylinder of the compound diameter. cylinder from'r the working cylinder and provided with a central opening therein; a piston rod. securedtosaid'working piston and extending through the opening-in said cap in iluid tight relation therewith into said compound cylinder; a composite piston mounted on the piston rod within said compound cylinder, said composite piston having coaxially nested piston elements, the outer of said piston elements having a diameter tting the length of greatest diameter of said compound cylinder; automatically releasable means initially holding said composite piston elements in alignment; and means for connecting the tool to be operated in uid tight relation to the device to receive the hydraulic uid at maximum pressure from the cylinder of least diameter of the compound cylinder of the device.

8. An operating device for tools functioning under hydrostatic pressure as set forth in claim 7 and in which said support tube is formed with a chamber to receive a charge of slow burning propellant; and means for igniting said propellant, the gas generated by the burning of said propellant being effective to open said flow controlling means.

9. An operating device for tools functioning under hydrostatic pressure as set forth in claim 7 and in which said working piston is formed with a central opening and a chamber in communication with said opening; a check valve mounted in said chamber to prevent reverse ilow of hydraulic fluid into the working cylinder; the said piston rod being provided with an axial bore communicating at its upper end with said recess, being closed at its lower end, said piston rod wall having ports therethrough positioned toward its lower end leading from said bore above the composite piston mounted on said piston rod into the space between said composite piston and the ycap of said compound diameter cylinder,

10. An operating device for tools functioning under hydrostatic pressure as set forth in claim 7 and in which said support tube is formed with a chamber to receive a charge of slow burning propellant; means for igniting said propellant, an elongated chamber in said support rod between the propellant chamber and the passages through the wall of the support tube; a piston like member provided with a depending portion mounted in said elongated chamber, the depending portion closing said passages in the inoperated condition of the device; and said support tube wall having a passage means therethrough leading gases generated by the slow burning propellant to said elongated chamber below said piston like member to cause movement thereof removing the depending portion from position closing said passages through the wall of the support tube.

11. An operating device for tools functioning under and asection of highresistance wireincluded in the elecf' tric circuit withinthe slowV burning propellant, and broughtfby the flow" of electric current therethrough to a temperature suflicient to cause ignition of the propellant.

12.. An operating device for toolsv functioning underr hydrostatic pressure, comprising: an elongated cylindrical casing having-.a fixed partition provided with an 'axial opening therethrough.. extending across an upper portion oftsaid casing; a supportv tube axially positioned in the upper portion ofthe Vcasing with its lower end secured in said partition. with-thev borethereof in alignment with the axial opening therein; a free piston slidably mounted on.ksaid support .tubein fluid tight-relation to thewalll of: the vcasing and. the surface of said support tube, the free4 piston Vbeing under thehydrostatic pressure; said support tube wall havingpassages therethroughpositioned adjacent the upper surface of said partition leadinginto the bore of the support tube; a rod arranged in the bore of-the ysupport tube, the lower end of said rod closing the .passagesat the. lower v.end 4 of the support tube until the rodfisraised. ajheadatftheupper endY o f said rod; means connecting the upper end of the support tube to a suspending cable down which a go-devil may be dropped; lever means mounted on the upper end of said casing in position to be struck by said go-devil and elective thereupon to engage the head of the rod and raise said rod to open the passages through said support tube to hydraulic fluid; a working piston in said casing below said partition in iluid tight sliding relation to the wall of the casing; the space above said working piston constituting a working cylinder receiving the hydraulic fluid owng out of the space between the free piston and xed partition; a piston rod secured -at its upper end to said piston; a compound diameter cylinder arranged coaxially with the working cylinder and having a plurality of lengths of progressively less diameter, and a maximum diameter less than that of the working cylinder; a cylinder cap separating said rst cylinder of the compound diameter cylinder from the working cylinder and provided with a central opening therein, the piston rod secured to said working piston extending through the opening in said cap vin uid tight relation therewith into said compound cylinder; a composite piston mounted on the piston rod within said compound cylinder, said composite piston having coaxially nested piston elements, the outer of said piston elements having a diameter fitting the length of greatest diameter of said compound cylinder; automatically releasable means holding said composite piston elements in alignment; and means for connecting the tool to be operated in fluid tight relation to the device to receive the hydraulic iluid at maximum pressure from the cylinder of least diameter of the compound cylinder of the device.

13. An operating device for tools functioning under hydrostatic pressure as set forth in claim 12 and in which said piston rod is tubular, the upper end of the piston rod being secured in a threaded recess in said working piston communicating with the working cylinder, said piston rod having a solid lower end andextending through the opening in said cap in uid tight relation therewith into said compound cylinder; and said tubular piston rod wall having a port discharging hydraulic uid into the space between the back of the composite piston and the cap of the compound diameter cylinder.

14. An operating device as set forth in claim 13 and in addition comprising a check valve arranged in the recess in said working piston and effective to prevent reverse ow of Huid through said tubular piston rod.

15. An operating device for tools functioning under hydrostatic pressure comprising: a rst cylinder adapted to be subjected to the hydrostatic pressure; said iirst cylinder having a passage adapted to admit the hydrostatic pressure to said first cylinder; a piston in said first cylinder acted on by said hydrostatic pressure; valve means effective to initially close said passage; means for moving said valve means to open said passage; a second cylinder co-axial with the first cylinder and of less diameter than said first cylinder; a piston rod extending from said piston into said smaller diameter cylinder; a compound piston in said second cylinder having a plurality of nested piston elements mounted on said piston rod; pressure sealing means between the piston elements; automatically releasable means initially holding said piston elements in nested relation to operate as a single piston but released on predetermined pressure being reached in said second cylinder, theY piston element of greatest diameter being iirst ereleased from the piston element of next smaller diameter; means preventing reverse movement in the second cylinder of the released piston element; and conduit means leading iluid under the pressure developed in said Second cylinder to means to be operated by the pressure tiuid.v

16. An operating device for tools functioning under hydrostatic pressure comprising: a vertical chamber open vat one end to the hydrostatic pressure of liquid in which the device is immersed and closed at its opposite end; hydraulic iluid positioned above said closed end of the chamber; freely movable means in said vertical chamber separating the liquid in which the device is immersed from the hydraulic uid in said chamber; a iirst cylinder adapted to be subjected to the pressure of said hydraulic fluidysaid first cylinder having a passage adapted to admit the hydraulic fluid under hydrostatic pressure to said first cylinder; valve means effective to initially close said passage; means for moving said valveto open said passage; a piston in said first cylinder, acted on by said hydraulic uid; a second cylinder co-axial with the first cylinder and of less diameter than the first cylinder; a piston rod extending from said piston into the smaller diameter cylinder; a compound piston having a plurality of lnested piston elements mounted on said piston rod in said second cylinder; pressure sealing means between the piston elements; automatically -releasable means initially holding said piston elements in nested relation but released on predetermined pressure being reached in the second cylinder, the piston element of greatest diameter being first released from the piston element of next smaller diameter; means preventing reverse movement of the released piston element in said second cylinder; and conduit means leading fiuid under the pressure developed in said second cylinder to means to be operated by the pressure fluid.

No references cited. 

